Cells and batteries having an alkali metal anode (negative electrode) and finely divided metal oxide cathode (positive electrode) are known. Particularly favored are such cells comprising a lithium foil anode of a thickness of about 75 microns, and an intercalation cathode layer of a similar thickness which contains finely divided transition metal oxide, electrically conductive carbon and solid electrolyte material. An electrolyte layer having a thickness of about 25 microns is positioned between the anode and cathode and often comprises an ion conducting polymer such as polyethylene oxide complexed with an ionizable alkali metal, preferably, lithium salt. The electrolyte layer separates the anode and cathode from one another while providing transport of ions between the anode and cathode. Typically, a current collector of conductive metal is positioned on both of the electrodes away from the electrolyte layer.
The cathode (positive electrode) provides for storage of lithium ions released from the anode (negative electrode) during discharge of the battery. Such ions are releasably retained by the cathode and then are transported back to the anode during charge. The cathode is a composite of ionically and electrically conductive materials disposed between the electrolyte layer and cathode current collector plate to provide the necessary transport between such components of the cell. There are two interfaces on the cathode side of the cell, the electrolyte-cathode interface and the cathode current collector interface. Failure of the cathode material to make good contact with the cathode current collector and with the solid electrolyte layer leads to an overall increase in cell impedance. This makes it difficult to recharge the cell.
It is desirable to further enhance contact between the positive electrode material and the respective materials of the current collector and the electrolyte layer at the interfaces so as to further reduce impedance.